The suicide of a nurse who accidentally gave an infant a fatal overdose last year at Seattle Children's hospital has closed an investigation but opened wounds for her friends and family members, as they struggle to comprehend a second tragedy.

Kimberly Hiatt, 50, a longtime critical-care nurse at Children's, took her own life April 3. As a result, the state's Nursing Commission last week closed its investigation of her actions in the Sept. 19 death of Kaia Zautner, a critically ill infant who died in part from complications from an overdose of calcium chloride.

After the infant's death, the hospital put Hiatt on administrative leave and soon dismissed her. In the months following, she battled to keep her nursing license in the hopes of continuing the work she loved, despite having made the deadly mistake, friends and family members said.

To satisfy state disciplinary authorities, she agreed to pay a fine and to undergo a four-year probationary period during which she would be supervised at any future nursing job when she gave medication, along with other conditions, said Sharon Crum of Issaquah, Hiatt's mother.